Sunday, May 10, 2009

Neutron Stars: Billions of Times Stronger Than Steel

Neutron Stars: Billions of Times Stronger Than Steel
New supercomputer simulations of the crusts of neutron stars--the rapidly spinning ashes left over from supernova explosions--reveal that they contain the densest and strongest material in the universe. So dense, in fact, that the gravity of the mountain-sized imperfections on the surfaces of these stars might actually jiggle spacetime itself. If so, neutron stars could offer new insights into a mysterious phenomenon known as gravity waves.

Neutron stars are the remnants of supernovae – basically the corpses of stars that were much more massive than our Sun. After the supernova explosion so much matter remains with no means to support itself (such as radiation pressure from thermonuclear reactions) that it all collapses into a relatively small object having a radius of about 12 km. The density of such an object is extremely high. Because the material is so dense, it is also very strong and rigid. Consequently, it does not collapse to a perfectly smooth sphere, but instead should contain surface imperfections roughly the size of (small) terrestrial mountains, each as massive as Earth.

In neutron stars that spin rapidly, the asymmetrical mass of these imperfections experiencing acceleration due to the periodic spinning motion should generate gravitational waves. The simulations that were performed in this research have shown that the energy in such gravitational waves could be a hundred times more than previously expected.

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4 Comments:

Blogger Desargues said...

...so much matter remains with no means to support itself...

I greatly enjoy your writing, and you do acquit yourself very honorably of the first duty of a science writer: to be clear, above all. But what does your phrase above mean, pray? What it is for matter to "support itself"? Do you mean some kind of repulsive force to keep atoms reasonably far apart from each other? Something else? Please, explain.

5/11/2009 06:37:00 AM  
Blogger Desargues said...

Also: are you still looking for beta testers? I belatedly came across your post form April 23. Sorry.

If you need people, I'd like to help out.

5/11/2009 06:42:00 AM  
Blogger Charles Daney said...

Also: are you still looking for beta testers?Yes, definitely. I'll provide information via email.

5/11/2009 04:38:00 PM  
Blogger Charles Daney said...

But what does your phrase above mean, pray? What it is for matter to "support itself"? Do you mean some kind of repulsive force to keep atoms reasonably far apart from each other?Yes, I mean a repulsive force. It's called Coulomb force, otherwise known as the repulsive force between two electrically charged objects with net charges of the same sign. In this case, the objects are protons. In an ordinary atomic nucleus, the protons are held together with neutrons by the nuclear binding force. But when the the matter is sufficiently dense, gravitational force overcomes the normal nuclear binding force and the Coulomb force. The matter collapses further until electrons combine with protons to make neutrons – which is why the thing is called a neutron star.

When there are almost no protons left, there are few charged particles either, hence little Coulomb force. Further collapse is eventually halted by the Pauli exclusion principle. See the Wikipedia articles for details.

5/11/2009 05:02:00 PM  

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